Yogurt Fermentation Process Control Detectors

Yogurt is a popular food category, with a global market size of over $125 Billion, and growing 6.5% per year.  Yogurt is rich in protein and calcium, had has the health benefits of beneficial gut bacteria, aiding the immune system and normalizing GI function.  The awareness of yogurt’s health benefits is a driver for its strong market growth.

The manufacture of yogurt includes a key fermentation step where the milk is held at 43-46 degrees C and a fermentation culture is added.  During this fermentation process, the fermentation bacteria metabolize certain compounds in the milk.  One by-product of this process is lactic acid, which contributes to the characteristic yogurt flavor.

Traditionally, the levels of lactic acid are monitored during the fermentation to determine when the yogurt is ready.  This lactic acid measurement involves taking a sample of the yogurt and titrating it with sodium hydroxide.  When the correct level is reached, the yogurt fermentation process is halted by rapidly cooling the mixture.

However, off-line testing takes time to give crucial process feedback. If the time-critical fermentation process is too short or too long it will produce inferior quality yogurt.  For example, if the fermentation process goes on too long, then other undesirable organisms may grow and give the yogurt disagreeable flavors and smells.

High quality fermented milk products can only be achieved with real-time on-line monitoring of the fermentation process.  The fermentation process is complex, and it is difficult to predict the proper end point of the process.  The pH probe has been used as an attempt at real-time process control, but due to maintenance and calibration issues, it is not considered to be reliable enough for monitoring industrial scale conditions.

In order to facilitate robust and reliable real-time yogurt fermentation process control, Photon Systems has demonstrated the use of DUV fluorescence spectroscopy to monitor the fermentation process and to precisely determine the proper end point of the reaction.  This allows the reaction to be stopped at precisely the right time, optimizing the quality and yield of the process.

Production of yogurt in a dairy factory, industrial equipment for filling in plastic cups

Key Issues

  • Real Time Process Control

    Sending samples to the lab and waiting is not acceptable for precise process control.  



The TraC can be fitted with liquid samplers, flow cells, or windows to look directly into mixing or bioreactor growth chambers process monitoring and for product quality control

TUCS 1000

The TUCS 1000 is a handheld instrument for providing detection of laser based detection of trace chemical in the fg amount or pg/cm² concentration range using deep UV fluorescence with excitation at 224.3 nm or 248.6 nm.

DUV Raman PL 200

A fully integrated lab model deep UV resonance Raman, fluorescence and photoluminescence spectrometer with microscopic imaging.l

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